A1 Journal article (refereed)
Colour alone matters : no predator generalization among morphs of an aposematic moth (2018)

Rönkä, K., De Pasqual, C., Mappes, J., Gordon, S., & Rojas Zuluaga, B. (2018). Colour alone matters : no predator generalization among morphs of an aposematic moth. Animal Behaviour, 135(January), 153-163. https://doi.org/10.1016/j.anbehav.2017.11.015

JYU authors or editors

Publication details

All authors or editors: Rönkä, Katja; De Pasqual, Chiara; Mappes, Johanna; Gordon, Swanne; Rojas Zuluaga, Bibiana

Journal or series: Animal Behaviour

ISSN: 0003-3472

eISSN: 1095-8282

Publication year: 2018

Volume: 135

Issue number: January

Pages range: 153-163

Publisher: Elsevier Ltd.

Place of Publication: Lontoo

Publication country: United Kingdom

Publication language: English

DOI: https://doi.org/10.1016/j.anbehav.2017.11.015

Publication open access: Not open

Publication channel open access: 

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/58291

Abstract

Local warning colour polymorphism, frequently observed in aposematic organisms, is evolutionarily puzzling. This is because variation in aposematic signals is expected to be selected against due to predators' difficulties associating several signals with a given unprofitable prey. One possible explanation for the existence of such variation is predator generalization, which occurs when predators learn to avoid one form and consequently avoid other sufficiently similar forms, relaxing selection for monomorphic signals. We tested this hypothesis by exposing the three different colour morphs of the aposematic wood tiger moth, Arctia plantaginis, existing in Finland to local wild-caught predators (blue tits, Cyanistes caeruleus). We designed artificial moths that varied only in their hindwing coloration (white, yellow and red) keeping other traits (e.g. wing pattern and size) constant. Thus, if the birds transferred their aversion of one morph to the other two we could infer that their visual appearances are sufficiently similar for predator generalization to take place. We found that, surprisingly, birds showed no preference or aversion for any of the three morphs presented. During the avoidance learning trials, birds learned to avoid the red morph considerably faster than the white or yellow morphs, confirming previous findings on the efficacy of red as a warning signal that facilitates predator learning. Birds did not generalize their learned avoidance of one colour morph to the other two morphs, suggesting that they pay more attention to conspicuous wing coloration than other traits. Our results are in accordance with previous findings that coloration plays a key role during avoidance learning and generalization, which has important implications for the evolution of mimicry. We conclude that, in the case of wood tiger moths, predator generalization is unlikely to explain the unexpected coexistence of different morphs.

Keywords: genetic polymorphism; moths; wood tiger; warning coloration; imitation (behaviour); imitation (artistic creation); predators; prey; learning

Free keywords: learning; polymorphism; predator-prey interactions; predator generalization; warning signals; wood tiger moth

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Ministry reporting: Yes

Reporting Year: 2018

JUFO rating: 2